Network access over Local Area Networks (LANs), Wireless LANs (WLANs) and cellular networks is becoming ubiquitous. It is therefore only a logical consequence that many mobile devices provide support for more than one Network Access Technique (NAT). From the perspective of modularity it is sometimes desirable to co-locate in one mobile apparatus two or more separate functional modules each supporting a different NAT. Such a modular approach facilitates re-using a functional module either in a stand-alone configuration or in any combination with other functional modules.
WO-A-00/22857 teaches a modular approach in which different network access modules (such as a Local Area Network (LAN) module and a Global System for Mobile communications (GSM) module) are interconnected via a communication bus according to the Universal Serial Bus (USB) standard. Other modules connected to the communication bus such as a Closed-Circuit Television (CCTV) module may then selectively transmit signals via the LAN module on the one hand or via the GSM module on the other.
A. Ghosh et al., “Open application environments in mobile devices: Focus on JME and Ericsson Mobile Functional modules”, Ericsson Review No. 2, Vol. 82, 2005, pages 82 to 91 (ISSN: 0014-0171) describe a further modular approach for mobile devices. This approach is based on a functional module in the form of mobile platform with a digital baseband processor supporting one or more Radio Access Techniques (RATs) such as General Packet Radio Service (GPRS), Enhanced Data for GSM Evolution (EDGE) or Wideband Code-Division Multiple Access (WCDMA). The mobile platform module is an environment that includes all the necessary integrated circuits and software needed to provide wireless network access services and communication services (e.g. for voice, data or multimedia applications), as well as interfaces to make these services available to applications residing within or logically on top of the mobile platform module.
Ghosh et al. propose to add a further functional module in the form of an application platform module having a third-party application processor to a mobile device when it is desired to run an open operating system such as Symbian. The application platform module will be co-located with the mobile platform module in the mobile device and will handle software applications including, for example, multimedia applications. The mobile platform module, on the other hand, will remain in charge of mobile functionalities (including all mobile communication tasks such as providing wireless network access) and mainly act as a network access module.
For the reasons set forth above, many mobile devices comprise two or more different functional modules. Often, such mobile devices will additionally be configured to provide services (such as network access services or application services) to external devices such as Personal Computers (PCs) and Laptops.